MFI adjusting tech manual

[304065]

Lex,

When your friend took the pump cover off to unstick the pistons, and now they are out of wack, well, that's the kind of thing that requires a rebuilder to get involved.

If you have been reading the technical material about how the pump works, you know that the six cylinders of the pump have small clamps on the sides. These clamps have gear teeth, as illustrated below.



Now, the way the pump changes the injection quantity is to rotate the cylinders, allowing more or less fuel into them. The cylinders are rotated through the action of the toothed rack in the photo acting against the toothed clamp.

In order to get the injection quantity the same between all six cylinders, the clamps are rotated slightly one way or the other, and then tightened down, then the injection quantity is measured on a special machine.


That's a SPICA pump being tested by Wes Ingram Enterprises, but you get the idea. Photo copyright http://www.wesingram.com/hp.htm

The danger is, if you don't have the injection quantity the same, the engine might run, but it won't run well, and if one jug is lean and the others rich, a meltdown is coming.

[Lexluther]

I dont mean any offense to anyone, and appreciate all the help I have received. As far as carbs, I have a friend who has a set, so If I want to go that route I have the option. But I would prefer to stay origional.

I think we can get the car lined out, and pump adjusted without spending $1000. This car is 34 years old, and we are learning more and more every day, I have been working on BMW's for 8 years, and have never had a problem, that couldnt be figured out, we have never had to take any of our cars to the dealer. If all our efforts fail, I guess I 'll have to trade her for a BMW...

[Grady Clay]

I, for one, know you mean no offence. Don’t worry about that.

In the Pelican tech link that Warren and I referenced you will find all the technical info about the pumps. You may just have to follow the links farther (and download some zipped pdf files.)

There are two distinctly approached here. You have found a BBS that is focused on DIY when possible yet recognizes limits. The other is to pay someone to do everything for you.

I don’t grind my own crankshaft. I send it to a professional, Porsche/BMW experienced crank grinder. On the other hand I can inspect a crankshaft to standards better than one can be ground.

Regardless, you must understand the technology so you can properly direct the process.

The same is true with MFI.

Since you have followed all the above links you know that a properly calibrated MFI pump is only part (small but important) of the overall picture. That is what CMA (and CMA2) is all about. The MFI pump is a part of a system. It is but one of many parts and all must work correctly for the system to properly function.

I appreciate your reticence to pay $1000 for a pump rebuild. Would you not pay for having a professional grind your BMW crankshaft or can you “clean it up” with some 800 grit?

BTW, I grew up in Louisville.

Best,
Grady

[Early_S_Man]

lex,

The 'Blue Book' [covers are blue poster stock paper on my original] offically called C,M,A is not a tutorial on the MFI system ... it is a guideline for tuning and troubleshooting by a technician that is expected to have been formally trained and expected to have the factory service manuals [volumes I & II for '65 - '71 models ... where the thory of operation of MFI is explained] at hand ...

The documents on the Pelican MFI Tips page are a good supplement to the factory manuals, and fill in the 'gaps' for those of us never exposed to factory training, which dealer mechanics were sent to back in the 1960s ...

For you to have declared all of this material as worthless after only skimming a few pages ... indicates an impatience that will guarantee failure. All of your BMW experience is worthless with respect to the MFI fuel injection system, since it obviously does NOT include 1972-76 BMW 2002 tii experience!

There are people here on Pelican who have mastered the MFI system, as well as repaired their CDI units and Speed Switches in the process ... without much documentation or training ... but, it took weeks or months of research and perseverance! Some professionals will tell you it is impossible to do as a DIY project, but there are exceptions ...

[Lexluther]

I wont never pay $1000 to have a crank turned either.

[svandamme]

well yeah , but you couldn't do it yourself either?

[Lexluther]

I dont have a problem paying someone to do a specific job, but machine shops will turn a crank or size rods, they ahve set prices for 4 and 6 cylinders, they dont care what its off of, as long as they have the specs for the piece. And its usually a fair price.

What I am saying is the money these guys charge for "fixing" this pump, which from what I am reading is not wore parts at all, but varnish from sitting, clogs etc. Its way too excessive!

[Oldporsche]

In many respects this isn't a reasonable car. Did you ever price the trigger for a door handle?

The rareness of the MFI has driven the repair and rebuilding of the pump to very expensive prices. I can remember giving $500 in 1983 for a 911E pump rbuild. Now 22 years later what would that price be? It's a complicated piece of machinery.

This situation of the repair price for induction systems is one of the driving forces behind the move to using EFI for replacement of the CIS on our cars. There are alternatives. When you look at carbs, they aren't all that cheap either. All of the alternatives will require compromises on your part.

It is conceivable that your pump wouldn't need rebuilding. Get on the phone with the rebuilders and talk to them. It might need some cleaning and recalibration.

David Duffield

[Zeke]

Lex, I am on your side. There is an ex off road/stadium racer here in Long Beach that is a maverick mechanic and has been all of his life. He was a winner too, always accused of cheating, but things always checked out legal at tech. He is just that kind of guy that understands things.

He has never heard of Henry or Gus and didn't know you could send the pumps out to specialist. He tears them apart all the time.

If you like working with minatures like models and teadious things of that nature, you could have done this pump. But, if your friend failed to note the settings mentioned above and put the thing together by "sight," well, you could be in for a job. However, taking it apart again is not the end of the world.

A well known contributor here once told me to turn the part load 7 clicks

(right there I stopped typing about an hour ago and went to take one of these suckers apart. I have 3 of them, a 2.4 T, a 2.2 S and E. What an amazing piece of equipment!)

Lex, I think you're a brave man. If I knew the E pump was good, I'd take all the measurements off the various rods and such and let you set yours up like this one. But this one has never run in my presence. It is supposed to be rebuilt, it's darn near brand new looking. But, I don't trust it. I'm sending mine out to have it calibrated.

Good luck to you.

[Lexluther]

Thanks! I appreciate the confidence. I love the Porsche 911 body style, but its just a car, and someone had to build it origionally, Look at it this way, for $1000, I can build my own setup to calibrate these pumps, then from here on out I would be able to correct mine any time I needed to, its not rocket surgery !

It all good, I will eventually figure it out. Next time we will take pic's AS we disassemble it... the we might have a better chance of getting the adjustments back right.

[spinmd]

Milt,

I've got a few E pumps that I'm hoping to find one that's the best for my 69E without have to rebuild the pump completely. What's the going rate for a recalibration vs. a rebuild? I didn't want to bother Gus or Henry with a price quote as I'm sure they're busy.

Thanks,

[HarryD]

Originally posted by spinmd
Milt,

I've got a few E pumps that I'm hoping to find one that's the best for my 69E without have to rebuild the pump completely. What's the going rate for a recalibration vs. a rebuild? I didn't want to bother Gus or Henry with a price quote as I'm sure they're busy.

Thanks,

You should ask them.

After all, if you are a bonfide customer, why would any service type business not want to give you a quote to perform one of their services?

[spinmd]

Harry,

Thanks, I've talked to both Henry and Gus for various issues and they are quite helpful but also very busy guys. I didn't feel the need to drag them from their work to answer the phone when I figured Milt already knew the going price. Besides, I'm not currently in the market to have the work done, just wanted a ballpark figure.

[HarryD]

Ron,

Fair enough.

[Zeke]

On this page, you will see the name "Fairchild." I suggest you call.

Now, one difference between one of the "famous" fuel injection services and Fairchild is the level of appearance. If you want beauty, you will pay for it.

[304065]

Did any of these pumps ever get put back together and work?

[jeff m]

Lex,
Adjust and recalibrate are very different.
Adjustment is easy (well sort of) calibration is different.

Following the advise already given could give you a working pump and you may not need to spend anything.

Adj is all in the CMA,... set pump timing, then access the adjments thro the back past the alt. with two easlily made tools.


Jeff

[BURN-BROS]

Lex, I feel for you and I can understand your thought process,but the vintage Porsche market is shinking everyday. Specializing in parts/service for these cars will continue to rise, pushing out all except the rich and passionate enthusiast. Parts are not readilly available to average Joe and they are extremely expensive to boot. You can however, convert to carbs and sell the MFI system or head off to a CIS model of 911

[jwernquist]

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Thanks
Jon

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[jwernquist]

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